Weekly Ag Update

 By ned birkey

msu EXTENSION EDUCATOR EMERITUS

SPARTAN AG

 The National Weather Service Climate Prediction Center’s outlook to July 14 called for a probability for above temperatures and a near normal outlook for precipitation. Eric Snodgrass, of Nutrien, thinks July overall will be near normal, with some cooler than normal temperatures and above normal precipitation. He also thinks there is significant leaf wetness crop disease risk, highest of the past 20 years, due to the air and moisture flow coming up from the Gulf and southern states. Heat stress is worse for crop growth than drought stress.

Crop lookout is a new interactive tool on the Crop Protection Network available to farmers and others at: https://cropprotectionnetwork.org/crop-lookout. This interactive map shows real-time what has been observed in fields.

Corn rootworm development can be partially forecast by when fireflies (lightning bugs) come out. I first noticed them on June 28, which means that the timing is right for corn rootworm to begin feeding, larvae on roots, causing leaf scarring, root pruning, stalk lodging and possible late-season goose necking of plants. Adults will clip silks and feed on ear tips, being attractive to late-planted corn. If the corn does not have a resistant genetic trait, then scouting should be a July activity. Dr. Chris DiFonzo suggests wearing a clear face visor to keep the corn leaves out of your face while walking fields. Scouting should continue for corn earworms and Western bean cutworms and European corn borers in late planted cornfields. Use the MSU/OSU Field Crop Insect Pest Management Guide, to get detailed scouting information and control recommendations.

Nutrient removal by the harvested grain portion of wheat must be accounted for when planning fertilizer rates for the next several crop rotations. One-hundred-bushel wheat will remove 50 pounds of P2O5, or ½ pound per bushel of yield and 25 pounds of K2O, or ¼ pound per bushel of yield. Every ton of dry wheat straw removes 12-14 pounds of nitrogen (N), 2-3.5 pounds of P2O5 (phosphorus) and 23-28 pounds of K2O (potassium).

Fertilizing the garden may not be top of mind to most gardeners in July. Now many vegetables are in the reproductive growth phase, meaning their nutrient uptake is higher than in the spring. Of course, the first step is always a soil test, done either in the fall or spring. Either organic or synthetic fertilizers, preferable slow release, can replace lost nutrients to ensure that soil nutrient levels are at acceptable levels for healthy plant growth. For most edible crops or perennial flowering plants, fertilizer is usually applied in the spring and mixed into the soil before planting or before plant growth begins. Season-long crops like corn, squash, tomatoes and potatoes can have extra fertilizer applied in-season. Different crops have different nutrient needs. Tomatoes, for example, don’t need much nitrogen mid-season but are heavy calcium users.